In the construction of residential homes and small commercial buildings, as well as other similar structures, the center sill support framework for the building typically comprises a perimeter sill secured around the foundation of the building and one or more center beams extending transversely across the foundation between the perimeter sill boards. The perimeter sill and the center beams are constructed with a support ledge or a bond timber running along their lower edges, which forms a shoulder for supporting the notched ends of the floor joists. The floor joists are mounted parallel to each other and extend transversely between the perimeter sill and the center beam to form an array of floor joist boards, which together with the center beam and the perimeter sill form the center sill support framework for the building.
The ends of the floor joist boards have a notched portion for mating with the bond timber of the support beam, either the center beam or the perimeter sill, in a manner so that the top longitudinal edge of the floor joist boards and the top longitudinal edges of the support beam are substantially in a common plane to provide a level surface for fastening the plywood and subflooring of the building. The cross-sectional dimensions of the bond timber are dictated by the structural loads of the building that the center beam or perimeter sill must support. For example, some building codes require a 2.times.2 inch bond timber when using a 2.times.8 inch floor joist, and a 2.times.4 inch bond timber when using a 2.times.10 inch or 2.times.12 inch floor joist. While the terms 2.times.2, 2.times.4, 2.times.8, 2.times.10, and 2.times.12 are referred to throughout the specification in terms of inches, it will be understood by those skilled in the art that the actual dimensions for the referenced boards are somewhat less, as is commonly understood in the construction industry.
A typical method for cutting floor joist boards utilizes a pattern board, which a carpenter cuts from a length floor joist lumber to the length of the floor joist boards required for a particular application. The carpenter then cuts notches in the lower corners of the floor joist pattern board with the dimensions of the notches being equivalent to the dimensions of the bond timber, as dictated by the height requirement of the floor joist boards. With the pattern board properly cut, usually two carpenters place the pattern board over an uncut length of floor joist lumber, and each carpenter traces with a marker along an end of the floor joist pattern board. The carpenters then remove the floor joist pattern board and each carpenter saws his end of the floor joist lumber and cuts out the marked notched portions to produce a floor joist board. The carpenters then place the floor joist pattern board on top of the next segment of the floor joist lumber and repeat the process.
A problem with this method for cutting floor joist boards is that it generally requires two carpenters to perform the cutting process in an efficient manner. One carpenter marks and saws one end of the floor joist board while the other carpenter marks and saws the other end of the floor joist board, and then together the two carpenters move the floor joist pattern board onto the next segment of the floor joist lumber. Such an operation is labor intensive.
Another problem with this method for marking the floor joist lumber is that the dimensions of the notched portion are measured from the lower edge of the floor joist board rather than from the top edge. As a result, any variances in the lumber appear along the top longitudinal edge of the floor joist board when mounted to a support beam and, thus, an unlevel surface can be created between the top edges of the floor joists and the top edges of the perimeter sill and center beams. Ideally, the top edges of the center sill support framework, that is the top edges of the floor joists, perimeter sill, and center beams, lie substantially in a common plane so that a level structural support framework is created to which the plywood and the subflooring can be attached.
Another problem with this method for cutting floor joist boards is that a different floor joist pattern board needs to be cut when the height dimension of the floor joist boards changes.
Accordingly, a heretofore unaddressed need exists for an apparatus for use by carpenters in marking and cutting floor joist boards that can be used by a single carpenter to mark and cut accurately and quickly the notches from the corners of the floor joist boards of varying dimension.